Massachusetts General Hospital’s planned $1 billion expansion in Boston will include many features to cope with a natural disaster.

The goal is to create a structure where patients and staff could potentially shelter in place for four days. A hospital spokesperson cited lessons learned from Hurricanes Katrina and Sandy in creating a new wing to be able to withstand a disaster and function afterwards.

The site is close to the Charles River in an area that was once a marsh. Flood-proofing the 13-story building, which will have 456 single occupancy rooms, is a top priority. The facility could be a place of a refuge for the whole hospital.

The hospital is already fortifying existing buildings built in 1940 and 1969, including moving critical operations out of basements and putting special protective coatings on windows and doors.